Multistep repeater motor



May 28, 1929.,

E. A. SPERRY, JR

MULTISTEP REPEATER MOTOR Filed Sept. 29. 1922 awuemtoz I w-w Patented May 28, 1929.

' UNIT-ED STATES PATENT OFFICE.-

MEN'IS TO THE SPERRY GYR-OSCOPE YORK.

'- ELMEB A. SPERRY; m, or BROOKLYN, NEW YORK, ASSIGNOB, BY MESNE ASSIGIF,

COMPANY, me, A CORPORATIQN or NEW MULTISTEP REPEATER MOTOR.

Application filed September 29, 1922. Serial No. 591,206.

I This invention relates to transmission systems for positioning an indicator or other device in accordance with the position of a remotely located element, and the present application is a continuation in part of my pending application, Serial No. 397,968, filed July 21, 1920, which pending application is assigned to the assignee of the present application.

More particularly, this invention relates to repeater motors employed in such systems, and has for its object the provision of means for obtaining clear cut definition of steps in the step by step rotation of the armature. This result I accomplish by localizing the magnetic'flux in each position the rotatable element may assume. Such localization is obtained by so forming the face of the field poles and of the armature, with projections.

or points, as to constitute auxiliary poles or points of maximum flux concentration for the difierent relative positions of the armature and pole faces.

My invention will be better understood from the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

' In the drawings, illustrating what I now consider the preferred forms of my invention;

' Fig. 1 is a plan view, partly in section, of an improved form of repeater motor, the top section of the motor casing being removed. F Fig. 2 is a vertical section on line 2-2 of Fig. 3 is a plan View of a modified form of repeater motor. with bodying my invention,

Fig. 4 is an enlarged vertical section of Fig. 3, I

Fig. 5 is an enlarged detail view of a part of Fig. 3 to more clearly illustrate applicants invention, and j I Fig. 6 is a wiring-diagram of a transmission system .in which the present invention may be employed.

Referring now to the drawings, in which the numeral 1, in Figs. 1 and 2 indicates a repeater motor, comprising a plurality of field poles 2, of which five are shown, and a parts broken away, em-

rotatable armature 3. Said poles and armature are shown mounted in a casing consisting of sections 4 and 5 bolted or otherwise secured together in any. suitable manner.

The armature maybe shown provided with- '13 and 14 respectively. By these means,

current may readily be led through the easing section 4 to brush 9 and in a similar manner through section 5 to brush 9'. Since the motor shown is a twenty-step motor, such as is disclosed in the aforementioned application, an indicator card 1 having twenty index references 1 is provided, and a pointer 7 is carried by the motor shaft 7 to cooperate with said card.

In practice, it is found that when the armature 3 moves through a given step, it ma occupy any one of a plurality of slightly di ferent angularpositions in which the action of the repeater motor is substantially the same.v In order to assure a clear cut definition of steps in the step by step rotation ofthe armature 3, that is, to insure that said armature will positively'assume but one position for each step, the faces of the poles and the armature are so shaped as to accomplish a sharp definition. As shown in Fig. 1, the pole pieces 2 are provided on their faces with projectors 2*, 2", and 2, and the armature 3 is likewise provided with projections 3, 8*, 3, 3 and 3, which projections serve as points for concentrating the magnetic flux and cooperate to prevent armature 3 from assuming more than one definite position for each step, since for each step of armature 3, the projections on the armature assume a definite position with respect to the cooperating field poles. This 0 eration will be more fully described hereina r.

While the armature 3 may be provided with a winding 6 rotatable. "therewith as 4 and 5, in which the winding is fixed. In the shown in Figs. 1 and 2, a repeater motor embodying my invention may i assume other. forms in which the armature'mayhave no winding, or itmay be as shown in Figs. 3,

1 latter three figures is shown a repeater motor,

certain features of the construction of which form no part oi my invention, this being claimed in the co-pending joint application of R. E. Kortepeterand A. A. Amundsen,- serial N 0. 519,058, filed December 1,1921, for repeater motor indicators, which application is also assigned to the assignee of the present application. The motor shown in Figs. 3,4 and 5, however, embodies my invention, clearly shown i115, from which it 'wiil be seen ,thatthe projections may assume va rious forms.

Referring to Figs. 3, 4 and 5, the numeral 7 15 indicates a repeatermotor having, a-plu'- casing 21 in any. suitable manner, such as rality of poles 16,- such as five, and a rotatable armature 17.v "Said poles and armature are shown mounted in a casing 18. The armature 17 is fixed to ashaft .19 in any suitable manner, which shaft is supported in suitable bearings 20', 21 in the casing 18. As shown in,

Fig. 4, the armature 17 consists of a cylindrical member 22, fixed on the shaft lginany.

. suitable manner, having secured at each end an oppositely'extending arm 23v and 24, respectively, of magnetic material, A winding 25 for the armature-17 surrounds the member 22 and is rigidly supported. within the by a cross-bar 26. It will'thus be seen that the armature 17 may rotate independently-of its winding 23. The poles 16 are shaped with a plurality of teeth 30, 31332, 33, which are separated by cut awayportions 34, to localize Y the magnetic" flux, and thereby obtain clear;

- cut definition ofsteps, as will" lie fully'dei scribed hereinafter.

-motor. I have for this reason shown five nection with Fig. "6, this system however bepair of'poles, such for example, where twenty steps maybe obtained within. five pole pole motors with polarizing'coils, the operation of which may be briefly described in coning claimed in my parent case] In Fig- 6, I have shown connections between a transmitter 38 and repea'tefmotor 16, which could-be ofeither type shown in Fig. 1 or Fig. 3, whereby-20 steps per revolution of the armature 17 may be obtained; The field windings 16", 16*, 16, 16, 16, are; all connected together at one end, and

each of said windings is connected at its otherjend to a respective one. of posts 41 and brushes 42. r In this figure I have designated.

the brushes 42 as 42, 42 42, 42 and 42,

according to the particular field coil to which each brush is connected. The direct current brushes 42', which posts and brushes are also connected with the terminals of the armature winding 23., which winding shoav'n as wound on the armature 17 although the winding could be arranged as shown Fig.. 4. I11 this manner, the armature 17 is constantly polarized. By so arranging the members 39 and40, which are insulated from :mains 43 are connected to posts 41"'and' I i? each other and constitute the rotatable element of the transmitter 38, andthe brushes 42, that as said element is turned, brushes 42 tain; twenty steps-0f armature 17 per reVo-. lution. Thus when the members 39 and 40 are in the POSitlOHSllOWIl in Fig. 6, so that members and current is caused to flow 'are alternatelybridged by twos andv threes in the proper sequence, I'am enabled'to -.ob-

brushes 42, 42, an'd42 are bridged by said through coil 16 -in such direction as to make the latter a south pole, and --through coils 16 and 16 in such direction as to make the latter' north poles, armature 17 will occupy. the position shown. If, now, said transmitter rotatable element isturned in'aclockwise direction a suflicientdistance from itsposition in Fig. 6, brushf42. will. no longer engage member 40, and repeater field coils 16. and 16 alone will beenergized. Armature 17 will thereupon move untilthe forces exerted by it by coils 16 and '16" are in equilibrium. (and will accordin 1y assume. a positionl18 degrees in' a cloc wise direction from its position .in Fig. 6. The members 39 and" 40 are. so designed and brushes 42? to 42 'so positioned that by the time the transmitter rotatable element has moved through 18 degrees, contact with a brush will be made .or broken and the number of repeater poles energized will be changed.

Thus, by the time said rotatable element has turned clockwise through 18 degrees from its position in Fig. 6, contact with brush 42 will have been broken. On the other hand, by the time that said element has been rotated in a counter-clockwise direction through 18 degrees from its position in Fig. 6, contact with brush 42 will have been broken, and armature 17 will consequently have assumed a position 18 degrees in a counter-clockwise direction from'its position in Fig. 6.

As said element isrotatedthrough degrees in a clockwise direction from its position in Fig.6, the repeater field poles will be energized as follows poles 16 and 16;

poles'16; 16", and 16; poles 16 and 16 poles "16", 16, and 16; poles 16" and 16; poles 16*, 16, and-16; poles 16 and 16;

. poles 16, 16, and 16 is reversed so that pole 16 becomes a north pole, thereby at tracting the S end of armature 17, and poles 16 and 16 become south poles and attract the N end of said armature. Continuing the rotation ofthe transmitter element clockwise through 180 degrees more, the polesare energized in thesame order as in the first 180 degrees rotation, although the current through them is, of course, reversed. It will thus readily be seen that as the transmitter element is moved through 360 degrees, the

armature 17 is caused to make a complete revolution in steps of 18 degrees each.

Since there are but five poles in the repeater motor for obtaining 20 steps, it is obvious that the armature thereof must assume twodefinite positions between a pair of poles,'or in other words, the armature occupies four difi'erent positions in advancing over the face of each pole.

To obtain a clear cut definition of steps in the step by step rotation of the armature, the

pole pieces and armature are shaped as above described to localize the magnetic flux in each position. With proper proportions then, the

repeater motor armature will occupy four positions for each pole. The operation of my invention will readily be understood by referring to Fig. 5, in which a clear cut defini tion of the four steps is-obtained in the following manner.

First p08z'ti0n.When approaching the pole marked 16*, the central portion 37 of the armature will lie with the upper edge thereof in line with'the edgefof the tooth 33' of the pole '16", thelower edge thereof being substantially in linewith the lower ed e'of the tooth 30 of the pole 16,

I 'eco'nd p0s-it'z'0n.Theupper-edge ofthe central pcrtion 37 will lie in line with the .ppperedge ofithe tooth 30 of the pole 16 and the lower edge will lie substantially in line with the lower edge of tooth 31.

Thi'1'd'p0siti0n.The two edges of portion 37 willcbe in line with the upper edge of tooth 31 and the lower edge of tooth 32.

Fourth posit-io'n.The two edges of por- -tion 37 will.bein line with the upper edge of tooth 32 and the lower edge of tooth 33.

The repeater motor described may .be pro-'.

vided with means for throwing the motor armature out ofits step positions when the currentis turned off, so that when-the current is turned on again, if the transmitter should hav'ebeen turned 'through'an angle of 180 degrees, the repeater-armature will not be held out of synchronism. This may be done by the means described in my parent case, or by the mechanism shown in' Fig. 3, in which a star wheel is fixed on the shaft-19,.

window 48 in the casing containing the apparatus. Mounted on the top of the motor and secured thereto at 49, is an electromagnet 50. Associated with the electromagnet is a bracket 51 having pivotally attached thereto at 53 a lever 52. Said lever carries a detent 54 at one end thereof which is adapted to engage the star wheel 45. A spring 55 map serve to hold the detent normally in engagement with the star wheel. The rear end of the lever 52 is adjacent the electromagnet 50, constituting the armature therefor. Thus, when the magnet is energized the action of spring 55 is overcome and the -detent 54 is disengaged from the star wheel.

On the lever 52. there is suitably fixed a bracket 56 carrying a resilient arm 57, which in turn carries a roller detent 58 adapted to engage the star wheel 46. The detent 58 is so positioned as to be disengaged from wheel 46 when detent 54 is in engagement with the wheel 45, and engaged therewith when detent 54 is disengaged. Since this particular apparatus is designed for a twenty-step .motor, the'card 47 has twenty references and the wheels 45 an d 46have twenty notches.

In the case of the wheel 46, which is fixed with respect to the reference card 47, the detent 58 is so positioned that when it is lodged in one of the notches of wheel 46, one of the references on said card 'will register with the window 48. The detent 54 is so positioned,

however, that when it is lodged in one of the notches of the star wheel 45, the armature 23 will occupy a position between its operatin step ositions, and the references on the car 47 W11] be outof register with the window 48,

thus indicating when the repeater motor is in o eratinn.

T e points of the, star wheel45' are shown f as sharp. while those of the wheel 46 may be cut off as indicated. By this construction it will be seen'that whatever position 45 may be. in when the detent 54 is brought into engagement therewith by the action of spring 55, the detent will find its way, to the bottom of the notches, while. the detent 58 may ride easily over the points of thewheel 46 and set'-' tle into the notches thereof only when the positions. H

The electromagnet 50 is preferably in the circuit ofthe armature winding 25 and is therefore constantly energized to hold the.

detent 54 011: of and the detent 58 in engagement with their respective star wheels,,when the apparatus is in operation, and when the motor armature is close to one of itsstep apparatus is not in operation, the deenergization' of magnet 50 will permit said detents to occupy their opposite positions. In view of the foregoing,a further description of the operation is not believed to be neces sary. m

As above indicated, applicants invention may assume diflferent forms. For-instance, the pole piece may be shaped with 3 points for localizing the flux, and the armature may have 5 of such points, asshown in Fig. 1, in which a clear cut definition of four'steps is obtained in the following manner;

' First position.When approaching the pole marked 2, thepoints 3 and 3-of the armature 3 will lie in line with the points of the pole 2.

Second positionr-f-Wheni the armature 'moves through 18degrees to this position,

the points 3 and 3 -will' lie in line with the points 2 'and 2 of the pole 2 respectively,

-. and the points 3 and 3will lie in line with the points 2 and 2 of the pole 2 respectively.

Third position-When the armature has again advanced through 18 degrees to this position, the point 3 of the armature will lie in line with the point 2of'the pole 2" 3o and the points 3, 3, and 3 will lie in line with thepoints 2", 2 and .2, respectively. A

-Fow-th position.When the armature has. 4 moved through its next step off18 degrees,

' armatureaid materially in accurate'defini-- 2 of the pole the points'3", 3, and 3 of the armature 3 will lie in line with the points 2, 2 and 2 of 4 the pole 2, respectively: v V

It will also be obvious-to those skilled in the results obtained in any .given case.

The total width of the armature and the total width of apole piece arepreferably different, that is, the: total width of the ar mature is preferably greater or smaller than P width than the distance between two ad acent the total wldth of the pole piece."

The total width of the armature may be somewhat less than the width of the pole piece, as shown Fig. '5. In this Case, the cut away end portions 35 and 36 of the tion, since while they assist in pulling over the armature fromone pole to another, they prevent the hanging or sticking of the armature to the pole which it is leaving by providing sufficient airgap at that polnt. It is also obvious that the same result .may be obtainedby making'the total width :of the armature greater than that oithe pole pieces, as shown in Fig. 1

In accordance 'atent statutes, I have herein described the principle of operation of my invention, to-

h the p rovisiolns" of the.

getherwith the apparatus, which I now considerto represent the best embodiment there- I of, but I desire to have it understood that Having herein "described (my invention,

what I claim and desire to secure by Letters Patent is:.'

1. In a repeater motor, a plurality of fixed poles,.a rotatable armature, a fixed coil for polarizing said armature, said poles and armature each being provided with a plu- \rality of cut away portions. to localize the magnetic flux in'a definite position for each position of the armature in passing across the face of the pole and additional mechanical means for aiding sharp step definition.

2. In a repeatermotor, a plurality of fixed poles, a. rotatable armature, a fixed coil for polarizing said. armature, said poles being provided with {number of teeth equal to the number of step positions the armature occupies in passing across said pole, and the armature being provide with cut away end portions providing a central raised part of,

greater width than the distance between .two of said teeth for the purpose specified.

3. In a multi-step repeater motor, aplurality of fixed spaced poles, and a rotatable armature, each of said poles'having spaced projections and said armature having re- 'duced end portions providing a central raised portion of greater width than the distance be tween two adjacent projections on. said poles.

4 In 'a multi-step repeater motor, a plurality of fixed spaced poles, and arotatable armature of less widththan the poles, each "of said poles having spaced projections and said" armature having reduced end ortions ovidlng a central ralsed portion 0 greater poles.

7 5. In a repeater motor, a plurality of fixed poles, arotatable armature? said poles being provided with a numberof teeth equal to the number of step positions the armature occupies in passing-across said pole, and the. armature being provided with put away end portions providing-a central raised part of greater width than the distance between two of said teeth for the purpose specified.

6. In a multi-step repeater motor, a plurality of fixed poles, a rotatable armature, each of said'poles having a plurality of spaced teeth equal in number to the step positions the armature occupies in passing across said pole, said poles being spaced from each other a distanceapproximately equal to a single step of the armature, and said armature being having a plurality of projections, means for provided with reduced end portions for the passing magnetic flux through said projec- 1o purpose specified. I V ticms, and auxiliary mechanical means for de- 7. In combination, a repeater motor-having fining the stop positions of the steps.

5 afield element and anarmature'element, each In testimonywhereof I have aifixed my of said elements comprising a plurality of signature. poles, one of said elements being rotatable 4 with respect toithe other, each of said poles ELMER A. SPERRY, J R. 

